Blanket lockup means for offset or wraparound ink blankets



H. J. LUEHRS July 25, 1967 BLANKET LOCKUP MEANS FOR OFFSET OR WRAPAROUND INK BLANKETS 3 Sheets-Sheet 1 Filed July 29, 1966 Ill INVENT I Hams JLue 14770RNEY July 25, 1967 H. J. 'LUEHRS 3,332,346

BLANKET LOCKUP MEANS FOR OFFSET OR WRAPAROUND INK BLANKBTS Filed July 29, 1966 3 Sheets-Sheet 2 INVENT Hans J Lue 5 QTTOENEY H. .1. LUEHRS 3,332,346

BLANKET LOCKUP MEANS FOR OFFSET OR WRAPAROUND INK BLANKETS July 25, 1967 3 Sheets-Sheet 3 Filed July 29, 1966 Han J 233/332 m ATTORNEY United States Patent 7 3,332,346 BLANKET LOtZKUP MEANS FOR OFFSET 0R WRAPAROUND INK BLANKETS Hans J. Luehrs, Westerly, R.I., assignor to The Cottrell Company, Westerly, R.I., a corporation of Delaware Filed July 29, 1966, Ser. No. 568,923 11 (Ilaims. (Cl. 101-4151) This invention relates to blanket lockup means for such blankets as are normally used in offset printing.

The purpose of this compact blanket lockup in comparison with existing more space-requiring lockups is to provide improved blanket cylinder rigidity, requisite for good printing, in combination with the application of a minimum number of simple components of sufficient physical strength to produce a dependable but low cost lockup mechanism employing standard manufacturing and assembly methods.

An object of the invention is to provide means to secure offset or ink blankets to a blanket cylinder wherein the tail end of said blanket is subjected to a given predetermined tension in a simple and direct manner to automatically take up any elongation of the blanket while printing.

Another object is to provide powerful and quick manual locking and unlocking means wherein the operator utilizes a suitable attachable lever or pin wrench to rotate the lockup mechanism through a limited arc of approximately 90 only for either operation in a single manual motion.

Another object is to provide a compact and simple blanket lockup assembly consisting of few components of exceptional strength so arranged as to require a minimum space within the blanket cylinder to retain maximum rigidity therein, an essential requisite for quality printing.

Another object is to provide a powerful blanket lockup wherein the blanket is automatically tensioned a predetermined amount while its metal clad head and tail end are inserted in suitable slots and subjected to clamping action and wherein the required clamping force is provided by the reaction of the tensioning force on the tail end of the blanket and the centrifugal force action on a floating clamping member in the rotating cylinder.

A further object is to provide a blanket lockup wherein the above and other objects may eifectively be attained as will appear from the detailed description of the invention set forth below.

It will be understood that my invention may be used on cylinders adapted for complete or partial wraparound blankets. Since I principally illustrate herein a complete wraparound blanket lockup and the other lockups mentioned require only a duplication of parts, the latter will not be further illustrated or described in detail.

Broadly, my invention comprises a longitudinally channelled cylinder having blanket lockup means located in the channel, said means being substantially free floating and subject to torque whereby the blanket is tensioned on the cylinder and said tension is automatically maintained and the blanket lockup assisted by the movement of same during the printing operation.

A practical embodiment of my invention is illustrated in the accompanying drawings in which:

FIG. 1 represents a plan view of one end of a cylinder embodying my invention which cylinder is partly broken away and partly in section to illustrate the several elements;

FIG. 1A is a fragmentary section on an enlarged scale, showing the central support for the reel or tube;

FIG. 2 is a view, on line IIII of FIG. 1 looking in the direction of the arrows;

FIG. 2A is a section taken on the line IIA-IIA of FIG. 1 looking in the direction of the arrows. The reactions of the elements to the tensioning and clamping forces are indicated by arrows.

3,332,346 Patented July 25, 1967 FIG. 3 is a top plan view of a fragment of the cylinder and bearer of FIG. 1 showing the relative locations of the collar, torque bar, split sleeve and pawl;

FIG. 4 represents an end view of the split collar;

FIG. 5 represents a side view of the blanket lead strip (closed);

FIG. 6 represents a side view of the blanket tail strip 1 FIG. 7 is a detail side view of the rotatable collar, rotation of which tensions the blanket on the cylinder and releases same as desired; and

FIG. 8 is a view looking in the direction of the arrows VII-VII on FIG. 7.

Referring to the accompanying drawings, a blanket cylinder 16, adapted in the present showing to carry at least one complete wraparound blanket 15 is channelled longitudinally and provided with milled out sections, including 17 and 18, to encompass my novel blanket lockup mechanism.

This mechanism comprises a free floating tubular reel member 7, provided with a cut-out section 32 which is adapted to receive the trailing edge of blanket 15. Said member 7 is provided with an internal hexagonal section 8 adapted to operatively engage a complementary hexagonal section of a torque bar 3. This center engagement is for the purpose of dividing up the torsional deflection of the reel under the load exerted against the blanket.

The torque bar 3 has a hexagonal end section 31, to receive a hex socket wrench for rotating the bar 3 during the initial set-up of the several elements.

Clamped to this hexagonal section of the bar 3, over split sleeve 4 which has a hexagonal interior, is a collar 2 held thereon by screw bolts 22, 23 seated in taps 26. Said collar 2 has a circumferential bore 21 adapted to receive a pin wrench 1 therein, which wrench may be swung through an arc of approximately to tension blanket 15 to or release it from the cylinder 16 as will be more fully described below. The collar 2 is also provided with a cut-out section 20 to receive a pawl 9, and also has stop sections 5 and 6 to engage the milled out portion 18 of cylinder 16 and thereby limit the rotative movement of said collar.

Pawl 9 is turnably mounted on stud 29 and is normally biased toward the collar 2 by spring 19 seated at one end in the cylinder, its other end engaging the pawl. Stud 29 is provided with a tapered thread 30 adapted to receive a pipe plug to expand stud 29 within the bearer for its retention therein. Slot 27 is provided to permit this expansion to secure stud 29 in the bearer.

A longitudinal filler piece 24- is bolted to cylinder 16 by bolts 25 so as to confine the reel or tube 7 and its associated members in a substantially free floating condition with respect to the longitudinal cylinder channel and the filler piece 24.

It will be understood that the filler piece outer edge matches the cylinder circumference but is so dimensioned as to leave a longitudinal slot across the cylinder circumference to receive the leading and trailing plate edges therein between the filler piece edge and the cylinder channel.

It will also be noted that the cylinder 16 is provided with a longitudinal groove or channel 36 which is adapted to and does, in fact, receive a spring rod 37 as shown in FIG. l. This spring rod 37 normally engages the outer surface of the reel 7 or the indentation 38 in said reel as will be more fully described below.

The parts are assembled as follows:

The spring rod 37 is laid in the longitudinal groove 36 and then the element 7 is placed in the longitudinal cylinder channel on top of the said spring rod 37 and filler piece 24 is secured to the cylinder 16. Torque rod 3, split sleeve 4, and collar 2 are located and associated as outlined above. With reel 7 in its open position, not shown, groove 38 will be in engagement with spring rod 37 to render reel 7 completely free floating to facilitate insertion and placement of the head end of the blanket in its proper position. A partial rotative motion imparted to the reel 7 in counter-clockwise direction (having reference to the upper portion of FIG. 2) will disengage spring rod 37 from groove 38 and raise reei 7 to confine and secure the head end 35 of blanket 15. It will be noted that the tail strip 34 of the blanket is subsequently engaged in a longitudinal reel slot 32. Further counterclockwise rotation of reel 7 and the final locked position is shown in the upper portion of FIG. 2.

Examination of FIGS. 5 and 6 will disclose the structure of the metal head and tail blanket engaging elements. It will be noted that the reverse fold of these metal elements 34 and 35, when subjected to the clamping as is illustrated in FIG. 2, securely engages the blanket so that it may safely be tensioned to the cylinder 16 in the desired manner without the danger of having the said metal elements separated or pulled away from the blanket 15.

A suitable tool, such as a hex socket wrench (not shown), is applied to end 31 of rod 3 to set-up initial torque prior to clamping collar 2 in its desired location.

In order to tension the blanket on the cylinder, the printing unit must first be located to prevent inching when torque is applied to lock the blanket on the cylinder.

The parts being in the abovedescribed relationship the blanket 16 is tensioned and maintained under tension on cylinder 15 as follows:

A pin wrench 1 is inserted in bore 21 in collar 2 and swung from right to left (FIG. 2). The said collar is rotated, putting increasing torque on rod 3 which rotates reel 7 due to the engagement of its internal hexagonal section 8 with the complementary section of rod 3. Collar 2 is rotated until pawl 9 falls into cut-out 20, being so urged by spring 19. At this point the blanket is tensioned on the cylinder as shown in FIG. 2 and the residual torque in rod 3 serves to automatically maintain blanket tension during the printing operation by acting against reel 7 for automatic takeup of the blanket.

It will be noted that torque bar 3 transmits rotative motion to reel 7 at its central position, through hexagonal section 8 thus distributing equalized torsional loads in both directions through the length of reel 7 to provide the tensional forces on blanket 15. The magnitude of these tensioning forces produced by the reaction of the torsional deflection of torque bar 3 is predetermined by the relative position of the clamped collar 2 to the reel 7, whereby a suflicient range of automatic takeup is provided to allow for blanket elongation during the printing operation.

Inspection of FIG. 2A will show, in combination with the blanket tensioning forces, other forces acting on the free floating reel 7, provided to clamp the head and tail ends of blanket 15 to additionally insure that the latter will be held to the rotating cylinder 16. Force designated by 11!, resulting from the reacting blanket tensioning force 11, plus centrifugal force 12 urge reel 7 centrally into the inverted wedge of approximately 45 formed by the cylinder filler piece 24 and the wall of the cylinder longitudinal cut-out. It Will be noted that the spring rod 37 also tends to urge the reel 7 centrally in addition to the centrifugal force on said reel when the cylinder is rotated. This serves to clamp blanket 15 and 13 with a corresponding reaction at 14. With increasing press speeds, clamping pressure at 13 will increase in proportion to the centrifugal force acting on the reel 7.

It will be noted that tube or reel 7 is substantially free floating, as outlined above and is supported in the cylinder longitudinal cut-out at its central portion only (FIG. 1) which allows for alignment of said reel to any blanket end piece irregularity while tensioning and clamping said blanket.

As clearly shown in FIG. 3, cylinder 16 is milled out only adjacent the bearers which permits all components except reel 7 to be removed with the bearers on the cylinder and the cylinder in the press.

It should also be noted that no deep drilling is necessary nor is precise alignment of the cylinder aperture in reference to the torque bar bearing within the cylinder bearer.

Since it is evident that changes may be made in the form, construction and arrangement of the several parts without departing from the spirit and scope of my invention, I do not intend to be limited to the specific embodiment herein shown and described except as set forth in the appended claims.

What I claim is:

1. In a blanket lockup for offset or wraparound ink blankets, the combination including a rotative cylinde having a longitudinal circumferential cut-out section and a longitudinal bottom groove in said cut-out section and a free floating blanket tensioning means confined in said section, said blanket tensioning means comprising a longitudinal free floating member, longitudinal grooves therein, at least one resilient means seated in said first groove and engaging a groove in said member, a second longitudinal member normally engaging the interior of the free floating member, a blanket tail edge receiving section of the free floating member, a blanket lead edge receiving section in said cut-out cylinder section, means for imparting rotation to the floating member through said second member for tensioning a blanket to the cylinder and other means for maintaining the blanket in tensioned condition thereon.

2. The combination according to claim 1 in which the free floating member comprises a tube having an interior hexagonal section for engagement by said second longitudinal member.

3. The combination according to claim 1 in which the second longitudinal member comprises a torque bar located axially internally of said longitudinal free floating member and in engagement therewith.

4. The combination according to claim 1 in which the means for imparting a rotation to said member through said second member comprise a collar adjustably fixed to said second member and means for imparting rotation to said collar.

5. The combination according to claim 1 in which the other means for maintaining the blanket in tensioned condition comprise a collar, a spring biased pawl and means on said collar adapted to receive one end of said pawl when the blanket is in its tensioned condition.

6. The combination according to claim 1 in which the second longitudinal member comprises a torque element of varied sections including a reduced section for torsional deflections to provide predetermined torque and enlarged end sections shaped to transmit torque to the longitudinal free floating member.

7. The combination according to claim 1 in which the longitudinal free floating member is a tubular reel and the second longitudinal member normally engaging the interior of said free floating member includes means engaging said reel at least at the center for reducing torsional deflection thereof during blanket tensioning 8. The combination according to claim 1 in which the longitudinal circumferential cut-out section has a raised portion for centrally supporting the longitudinal free floating member whereby same is self-aligning during blanket tensioning to allow for inaccuracy in any blanket section contacted thereby when a blanket is being tensioned.

9. The combination according to claim 1 in which the cylinder has bearers, the longitudinal circumferential cutout section is more widely recessed at its ends and the cylinder ends have longitudinal bores terminating in said recessed ends whereby the second longitudinal member, the means for imparting rotation and the other means for maintaing the blanket under tension may be assembled and disassembled while the cylinder is in the press without remOVal of the bearers or the filler piece.

10. The combination according to claim 1 in which the second longitudinal member normally engaging the interior of said free floating member comprises a self-aligning flexible torque bar.

11. In a blanket lockup for offset or Wraparound ink blankets, the combination including a rotative cylinder having a longitudinal circumferential cut-out section and a longitudinal bottom groove in said cut-out section, a filler piece rem'ovably fixed along one side of said cut-out circumferential section and a free floating blanket tensioning means confined in said section by said filler piece, said blanket tensioning means comprising a longitudinal free floating member, longitudinal grooves therein, a longitudinal spring seated in said cylinder bottom groove engaging a groove in said member, a second longitudinal member normally engaging the interior of the free floating member, a blanket tail edge receiving section of the free floating member, a blanket lead edge receiving section is said cut-out cylinder section, means for imparting rotation to the floating member through said second member for tensioning a blanket to the cylinder and other means for maintaining the blanket in tensioned condition thereon.

References Cited UNITED STATES PATENTS ROBERT E. PULFREY, Primary Examiner. F. A. WINANS, Assistant Examiner. 

1. IN A BLANKET LOCKUP FOR OFFSET OR WRAPAROUND INK BLANKETS, THE COMBINATION INCLUDING A ROTATIVE CYLINDER HAVING A LONGITUDINAL CIRCUMFERENTIAL CUT-OUT SECTION AND A LONGITUDINAL BOTTOM GROOVE IN SIAD CUT-OUT SECTION AND A FREE FLOATING BLANKET TENSIONING MEANS CONFINED IN SAID SECTION, SAID BLANKET TENSIONING MEANS COMPRISING A LONGITUDINAL FREE FLOATING MEMBER, LONGITUDINAL GROOVES THEREIN, AT LEAST ONE RESILIENT MEANS SEATED IN SAID FIRST GROOVE AND ENGAGING A GROOVE IN SAID MEMBER, A SECOND LONGITUDINAL MEMBER NORMALLY ENGAGING THE INTERIOR OF THE FREE FLOATING MEMBER, A BLANKET TAIL EDGE RECEIVING SECTION OF THE FREE FLOATING MEMBER, A BLANKET LEAD EDGE RECEIVING SECTION IN SAID CUT-OUT CYLINDER SECTION, MEANS FOR IMPARTING ROTATION TO THE FLOATING MEMBER THROUGH SAID SECOND MEMBER FOR TENSIONING A BLANKET TO THE CYLINDER AND OTHER MEANS FOR MAINTAINING THE BLANKET IN TENSIONED CONDITION THEREON. 